1+1/sin(alpha) =4 the range is for alpha is from 0 to 360 find alpha???

I got the first angle as 19.5, however, the marking scheme stated that there is another angle(160.5) can you please explain how they got the second angle

1 Answer
Nov 17, 2017

See below.

Explanation:

We have:

#(sin alpha + 1)/sinalpha = 4#

#sinalpha + 1 = 4sinalpha #

#1 = 3sinalpha#

#sinalpha = 1/3#

#alpha = 19.5 and ?#

We know that sine is positive in the first and second quadrants, thus the reference angle for the second value of alpha is going to be #19.5˚#, or #alpha_2 = 180˚ - 19.5˚ = 160.5˚#.

As required.

Hopefully this helps!